Thermal insulating sealing material around a radiator

ABSTRACT

This thermal insulating sealing material can prevent breakage due to freezing. Formed from a water repellent urethane foam by mold forming. The impregnation of water during a car wash or rainy weather is prevented.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a thermal insulating sealing materialprovided and arranged around a radiator and that elastically contactsthe bottom part of a cab to inhibit heat from an engine from flowingaround to the front of the radiator.

2. Description of the Related Art

In an industrial vehicle, such as a truck, the engine room is confinedand there is little available space because the cab is arranged on topof the engine. Consequently, as shown in FIG. 2, a structure is employedwherein a radiator 101 is arranged in front of an engine 100, and whileoutside air is drawn in by a cooling fan 102 provided on the frontsurface side of the engine 100 rearward of the radiator 101, heat isexchanged with the radiator 101, after which the air passes through theperiphery of the engine 100 and is then exhausted outside the vehiclefrom an outlet 104 provided in a lower cover 103 of the engine room.

Incidentally, there is a problem in that the air that was heated bypassing through the radiator and then further heated by the heat of theengine travels frontward along the bottom part of a cab 200 or thesidewalls of the engine room, causing a drop in the heat exchangefunction of the radiator 101. Particularly in recent years, the adoptionof fuel injection type engines has led to a trend in which engines havehigher output with the engine itself running at increasingly highertemperatures, making it necessary to increase the cooling efficiency ofthe engine and the heat exchange function of the radiator 101.

Accordingly, as disclosed in, for example, Japanese Unexamined UtilityModel Publication No. 05-065762 or Japanese Unexamined PatentPublication (KOKAI) No. 2000-204590, a partitioning member 300 made of aflame retardant resin foam is disposed around the radiator 101 so thatthe hot air present behind the radiator 101 does not flow around to thefront of the radiator 101. This partitioning member 300 is formed in aframe shape corresponding to the external shape of the radiator 101, itsupper surface elastically contacts a floor undersurface of the cab 200,and both side surfaces elastically contact the sidewalls, and the like,of the engine room, thereby exhibiting sealing properties and preventingthe flow of hot air present behind the radiator 101 around to the frontof the radiator 101.

This partitioning member 300 is generally formed in a prescribed frameshape from urethane resin foam, and is used by bonding it to theradiator 101 with two-sided tape and the like, or by coupling it withbolts and the like. Urethane foam is ideal as a thermal insulatingsealing material around the radiator 101 because it has low thermalconductivity, it is lightweight, and moreover it has excellent trackingcharacteristics due to its elasticity.

Incidentally, in the case of a vehicle used in a cold region, if waterthat has impregnated the partitioning member during a car wash or rainyweather, then it may freeze to the opposite member at the elasticcontact portion. Further, there is a problem in that, if the cab 200 isshaken, such as during inspection of the engine room, and thepartitioning member 300 breaks at the frozen portion, then the sealingproperties will decrease dramatically, leaving no choice but to replacethe partitioning member 300.

Furthermore, although Japanese Unexamined Patent Publication (KOKAI) No.2000-220467 recites a sound insulating material made of a lowhydrophilic urethane foam, it does not recite or suggest its applicationas a thermal insulating sealing material around a radiator.

SUMMARY OF THE INVENTION

The present invention takes the abovementioned circumstances intoconsideration, and has an object to prevent breakage due to freezing.

A thermal insulating sealing material around a radiator of the presentinvention that solves the abovementioned problems is a thermalinsulating sealing material provided and arranged around a radiator andthat inhibits the flow of heat from an engine around to the front of theradiator by elastically contacting the bottom part of a cab, wherein thethermal insulating sealing material comprises a water repellent urethanefoam.

It is particularly preferable that the water repellent urethane foamcontains a fluoro surfactant. In addition, it is preferably formed bymold forming.

The thermal insulating sealing material of the present inventionprevents the impregnation of water during a car wash or rainy weatherbecause it is formed from a water repellent urethane foam. Accordingly,breakage due to freezing in cold regions is prevented, enabling it to beused for a long time.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view that depicts the state wherein the thermalinsulating sealing material of the first embodiment according to thepresent invention is attached to a radiator.

FIG. 2 is a schematic cross sectional view that depicts theconfiguration of an engine room having the thermal insulating sealingmaterial.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The thermal insulating sealing material of the present inventioncomprises a water repellent urethane foam. For the water repellenturethane foam, one in which a water repellent agent is bonded to atypical urethane foam, one in which a water repellent agent is includedin the skeleton of the urethane foam, one in which the molecularskeleton of the urethane foam has a water repellent group, or the like,can be used.

There are fluorine based and silicone based water repellent agents,which can be adhered to a urethane foam by a method that coats byspraying and the like. However, with this method, unevenness in thecoating tends to arise because it is difficult to make visualconfirmation, even if there are uncovered portions, and this deficiencytends to occur in cases where the urethane foam has a complex shape. Inaddition, there is a risk of freezing if exposed to a large quantity ofwater causing the water repellence to become insufficient. In addition,although it is possible to adhere a water repellent solution using amethod such as impregnating and then drying the urethane foam, there isa problem in that the process is complicated.

Therefore, it is preferable to use a urethane foam that includes a waterrepellent agent in the skeleton of the foam. This type of urethane foamcan be manufactured by mixing in advance a water repellent agent in theresin foam raw ingredients, and foam forming in the presence of thewater repellent agent. If manufacturing with this method, it ispreferable to use a fluoro surfactant as the water repellent agent.

For example, with respect to 100 parts by weight of the total amount ofa polyol component and a polyisocyanate component, the fluoro surfactantis mixed at a proportion of 0.1-5 parts by weight, and foamed. For thefluoro surfactant, it is preferable to use one having an organic groupwith a fluoroaliphatic group having a carbon number of 3-20,particularly 6-12, and having an affinity for polyurethane resin. Thecompatibility with the polyurethane resin thereby increases. Withinthese, one having a perfluoro alkyl group is preferable.

If a resin having a water repellent substituent, such as the fluorinegroup, is used in at least one of the polyol component and thepolyisocyanate component, then a urethane foam having a water repellentgroup inside the molecular skeleton can be manufactured. If such aurethane foam is used, the water repellent agent will not be desorbed,and high water repellence can therefore be maintained over a long timeperiod.

Although it is possible to make the thermal insulating sealing materialaround the radiator in the present invention a prescribed shape bymethods such as cutting the urethane foam, it is preferable to use, asis, urethane foam of a prescribed shape formed by mold forming. Becauseurethane foam formed by mold forming has an integral skin layer on thesurface, the impregnation of water internally can be further suppressed,and freezing can be further prevented. In addition, if forming by moldforming, even complex seal shapes can be accommodated inexpensively. Inparticular, if using a urethane foam that includes a water repellentagent in the skeleton of the foam and that has an integral skin layer,then the water repellence can be particularly increased.

The thermal insulating sealing material around the radiator of thepresent invention has a shape that exhibits sealing properties bywrapping around the radiator, elastically contacting the floorundersurface of the cab, and by both sides elastically contacting thesidewalls and the like of the engine room. The means of fixing to theradiator is not particularly limited to two-sided tape, bolts, clawengagement, and the like.

Embodiments

The following concretely explains the present invention by embodimentsand a comparative example.

First Embodiment

FIG. 1 depicts a perspective view of a radiator provided with thethermal insulating sealing material of the present embodiment. A thermalinsulating sealing material 1 is formed substantially U-shaped, and isbonded to a radiator 2 by a bolt so that it contacts the upper surfaceand both lateral surfaces of the radiator 2. A steel plate (not shown)for fixing the bolts is integrally formed in the thermal insulatingsealing material. The same as FIG. 2, the upper surface of the thermalinsulating sealing material 1 elastically contacts the floorundersurface of the cab, and both lateral surfaces elastically contactthe inner surface of the sidewalls of the engine room, therebypreventing the hot air of the engine room from flowing around to thefront of the radiator 2, and preventing a drop in the cooling efficiencyof the radiator 2.

The thermal insulating sealing material 1 comprises a urethane foamprovided with water repellence, and its entirety is integrallymanufactured by mold forming. The following explains the method ofmanufacturing the thermal insulating sealing material 1, and substitutesfor a detailed explanation of the composition.

The polyol component was prepared by mixing, with respect to 100 partsby weight of polyol (“Sumifine 3063” polyether polyol made by SumikaBayer Urethane Co., Ltd., OH value=28, functional group=3), 0.15 partsby weight of a fluoro surfactant (“Megafac EXP.TF1068SF” made byDainippon Ink and Chemicals, Inc., 60% solid content), 2.5 parts byweight of water, 1.3 parts by weight of an amine catalyst, and 0.5 partsby weight of a foaming agent.

Meanwhile, denatured MDI (NCO=30-31%) was used as an isocyanatecomponent and mixed with the abovementioned polyol component at a mixingratio of NCO/OH=0.95, injected into a mold having a cavity the shape ofthe thermal insulating sealing material 1, and foamed at 40°-70° C. for10-30 minutes. The thermal insulating sealing material 1 obtained had anintegral skin layer over its entire surface.

Furthermore, simultaneous with forming the thermal insulating sealingmaterial 1, a test piece having dimensions of 100×100×50 mm was moldformed using the same raw ingredients, and submitted for testing,discussed later. An integral skin layer was formed across the entiresurface of this test piece.

Second Embodiment

The same as in the first embodiment, a test piece having dimensions of100×100×50 mm was made by forming the urethane foam with a somewhatlarger mold, and then peeling off the integral skin layer. In otherwords, the test piece of the present embodiment is the same as the onein the first embodiment except it does not have an integral skin layer.

COMPARATIVE EXAMPLE 1

The test piece of the comparative example 1 was manufactured the same asin the first embodiment using a polyol component the same as in thefirst embodiment except that it does not include the fluoro surfactant.An integral skin layer was formed across the entire surface of this testpiece.

Third Embodiment

The entire surface of the test piece of the comparative example 1 wassprayed with a silicone based water repellent agent (“Cosmo SiliconSpray” made by Tsuchiya Co., Ltd.) in an amount of 10 g/m² to make thetest piece of the present embodiment.

Testing and Evaluation

The test pieces of the embodiments and the comparative example weremounted horizontally, and a water absorption test was performed bydumping from above at a height of 50 cm 1 L of water for approximately20 s. This water absorption test was performed twice, and Table 1 liststhe measurement results for the amount of water absorption based on thedifference between the weight before water absorption and the weightafter the first and second water absorptions. In addition, thepercentage of water absorption was calculated after the second waterabsorption test, and that result is shown in Table 1. Furthermore, thistest was respectively performed for different test pieces A, B. TABLE 1Amount of Water Absorption Water (g) Absorption Skin Initial WeightFirst Second Percentage Layer (g) Time Time (%) First Urethane Yes A50.4 12.4 15.8 31.3 Embodiment containing B 51.5 11.1 13.6 26.4 a waterrepellent agent Second Urethane No A 50.7 18.2 23.4 46.2 Embodimentcontaining B 51.2 19.5 24.4 47.7 a water repellent agent Third Coatedwith Yes A 50.8 16.2 21.6 42.6 Embodiment a water B 50.7 15.8 21.6 42.7repellent agent Comparative Urethane Yes A 51.2 16.8 24.6 48.0 Example 1without a B 53.5 17.0 27.6 51.6 water repellent agent

It can be seen in Table 1 that the water absorption percentage for thetest piece of each embodiment is lower compared with the comparativeexample 1, thereby demonstrating water repellence. In addition, it isclear from a mutual comparison of the embodiments that using a urethanefoam having a water repellent agent in the skeleton and moreover thetest piece of the first embodiment having an integral skin layer haveparticularly excellent water repellence, and are ideally suited as thethermal insulating sealing material around the radiator. The secondembodiment also demonstrates an advantageous effect, but falls short ofthe first embodiment. Further, the water repellence decreases greatly inthe second embodiment, which does not have an integral skin layer, evenwith a urethane foam having a water repellent agent in the skeleton, andit is therefore understood that it is preferable to have an integralskin layer, i.e., to manufacture by mold forming.

1. A thermal insulating sealing material provided and arranged around aradiator and that inhibits the flow of heat from an engine around to thefront of the radiator by elastically contacting the bottom part of acab, wherein said thermal insulating sealing material comprises a waterrepellent urethane foam.
 2. The thermal insulating sealing materialaround the radiator as recited in claim 1, wherein said water repellenturethane foam contains a fluoro surfactant.
 3. The thermal insulatingsealing material around the radiator as recited in claim 1 or claim 2,wherein said water repellent urethane foam has an integral skin layer onsaid water repellent urethane foam which is mold formed.